Question: What is the binary star with the minimum luminosity whose instance of is binary star?
Paraphrase: Which is the binary star with the lowest luminosity, whose instance of is binary star?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q50053 . ?ent wdt:P2060 ?obj . ?ent wdt:P31 wd:Q50053. } ORDER BY ASC(?obj)LIMIT 5 
Answer: Lalande 21185, Proxima Centauri, 2M1207, Kepler-16, Kepler-411